In this project 10-15 normal donors will be selected for studies of autologous platemet storage. The intent of this study is to compare preparation of platelets by standard procedures and preparation of platelets using an integral filtration device which depletes white cells from platelet-rich plasma prior to the centrifugation steps used to produce the platelet concentrate. In this study each of the 10-15 donors will serve as his own control and will receive Chromium-51 labelled autologous platelets for determining in vivo recovery.